The SOMM Journal

June / July 2017

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22 { THE SOMM JOURNAL } JUNE/JULY 2017
{
getting geeky
}
IN THE CURRENT STATE OF not only the wine business but the food industry in gen-
eral, much of the populace gravitates toward terms such as "natural" and "organic." The
past few decades of mass production have inspired a movement back to homemade and
small production. As the pendulum swings, though, sometimes the bigger picture gets lost.
Is native yeast fermentation innately a better choice, or is inoculating with commercial
yeast not as taboo as the reputation it has garnered?
Let's start with the general truths of fermentation yeasts. Ambient yeasts are floating
around in the atmosphere, and fermentation will start spontaneously if the grape must
lies in warm enough conditions. Yeast genera such as Candida, Kloeckera, Metschnikowia,
Pichia and Brettanomyces can all be present in the unfermented juice, and yeast, as do
all living organisms, operate on the survival-of-the-fittest model. As the fermentation
temperature increases and nutrients deplete, Saccharomyces cerevisiae will inevitably
dominate, the other yeast strains dying once the must reaches approximately six percent
alcohol by volume.
So, is it better to allow the native yeast to begin the fermentation in the interest of
developing various aromas, or is it preferable to immediately introduce a commercial
strain of Saccharomyces cerevisiae in order to fully control the fermentation? Recent
panels at Somm Journal events have included several winemakers among whom inter
-
esting dialogue developed, with vintners advocating very different philosophies of and
approaches to their choice of yeast. This piqued my interest.
In large production, inoculation with Saccharomyces cerevisiae is a no-brainer—there's
too much at risk to relinquish control of something so vital. In small production, I was
always under the impression that natural yeast automatically yields a higher-quality prod
-
uct, but I am now reconsidering that concept. While it is surely true that the ambient
yeast generate unique aromas, different strains of Saccharomyces cerevisiae also elicit
distinct aromas when matched with various clones of grape varieties. Researching and
deliberately choosing the resulting aromas delivers a high-quality product too.
Another interesting thought introduced was the idea that native yeast fermentation
may not really be all that native. Unless the facility in which a wine is fermented is brand
new, without
any previous
ferments, the natural selection concept of yeast suggests that
Saccharomyces cerevisiae likely subverts any other yeast in the facility, meaning that native
fermentation may even be instigated by Saccharomyces cerevisiae itself.
One last consideration involves the idea of terroir. Many believers in native yeast
fermentation stem from a minimalist approach to winemaking in general, a view I gener
-
ally support, so when the idea was introduced that native yeast fermentation may hinder
terroir expression, I was again intrigued. The argument suggested that allowing several
different yeasts to begin the fermentation, while encouraging complex aromatics, also
grants that expression to the yeast rather than to the grape and site. Does inoculating
with one yeast strain, then, allow the overall terroir to emerge in the wine instead?
Ultimately, all that I have resolved is that yeast presents yet another choice in winemaking,
another tool in the toolbox, just like choosing an oak barrel treatment or whether to fine or
filter. Whether electing to rely on natural yeast or actively selecting yeast to initiate fermenta
-
tion, the choice aligns with a winemaker's overall philosophy, and no choice can be wrong.
PHOTO:
FOTOLESNIK
VIA
THINKSTOCK
Exploring the
Virtues of Yeast
by Allyson Gorsuch
Ultimately, yeast
simply presents yet
another choice in
winemaking.